It's necessary to build a support system, using slats of wood, wire-mesh fencing, pipes or poles and wire.

You'll spend more time pruning and training the plants - at least some time each week.

You'll harvest fewer tomatoes per plant because some pruning will be necessary.

Trellised tomatoes are more susceptible to sun-scald because they get less shade from leafy growth.

How to Trellis

A good trellising system uses four-foot stakes placed at five-foot intervals down the row with three wires running horizontally a foot apart between them.

As the tomatoes start to grow, train them so their branches interweave around and through the wires. Train two to three main stems per plant, and keep all the other side shoots picked off. (These shoots, which sprout from the crotch where the branches grow from the main stem, are called "suckers.") Tie some of the stems to the wires for extra support.

When the tallest branch grows beyond the top wire, cut it off. This stops the branch from growing any higher. If it grows too far over the upper wire, it will break off anyway.